An exercise apparatus includes a frame; a platform configured to receive a person in a standing position, the platform connected to the frame; a handheld component configured to be held by a person standing on the platform; and an impeller-driven fluid circulation system. Manipulation of the handheld component by a person standing on the platform results in driving of the impeller and circulation of fluid within the fluid circulation system. The platform may rock from side to side, whereby a person standing on the platform must maintain balance while manipulating the handheld component. The handheld component may simulate a paddle and may include an elongate shaft. In this respect, the paddle component is used by a person standing on the platform as if the paddle component were a paddle used in paddleboarding, including manipulating the paddle component through a rowing motion that preferably would be experienced when actually paddleboarding.